Disclosed herein are phase change ink imaging, transfix or transfuse members useful in ink jet, such as phase change ink or solid ink jet apparatuses. The imaging members can be imaging, transfix, transfuse, or the like, members useful in ink jet machines. In an embodiment, the release agent is a perfluorinated polyether release agent. In embodiments, the release agent has pendant functional groups. In embodiments, the release agent comprises a functional perfluorinated polyether material and a functional silicone material.
U.S. Pat. No. 6,695,904 teaches use of a perfluoroalkyl polyether as a release agent.
U.S. Pat. No. 4,430,406 teaches use of perfluoroalkyl polyethers as release agents.
Maintaining release surfaces in various marking engine subsystems is approached in a variety of manners, most often by use of release agents. Release agents wet surfaces in marking engines by physical or chemical means, providing a continuous barrier to toner, ink, and additives. The release agent is replenished by release agent management (RAM), drum maintenance (DM) or translating web oiling systems.
The following are shortfalls in performance, and are barriers to increased release life, expansion of high-speed color marking, and reduction of total cost of ownership to customers (TCO). To begin with, chemical and physical interactions between silicone release agents and toner and/or ink constituents leads to insufficient releasability.
In some commercial high-speed black and white products, fluorine-substituted silicones have been used as release agents at very low levels (<1 mg/pg) for enhanced performance. For many known marking engines, silicone-based release fluids are used because of their thermal stability and by virtue of the facility for functional side chain addition to silicone fluids used for chemical anchoring to substrates. These fluorine-substituted silicones provide fluids with enhanced resistance to interaction with ink and ink components, but are limited to specific applications and subsystem materials sets.
Fluorinated fluids, due to their non-interactivity with other materials, will allow an overall reduction in oil usage. The non-interactive nature increases their effectiveness as release fluids. In addition, these fluids can be effectively filtered and reused, which is an improvement over silicone fluids. Silicones interact so extensively with ink and wax ingredients, that gelation rates and viscosity increase while residing in the sump.
The performance of several end use applications in high-speed color printing is compromised by the residual silicone oil that remains on the surface of the print after fusing. Experience has demonstrated that fluorine-substituted silicone fluids avoid this issue because they diffuse into the paper faster than amine-functional silicone fluids, as they do not bond with paper fibers and fillers. Therefore, non-interactive fluorinated fluids should improve end use performance in printing applications where bookbinding adhesives, overcoat varnishes, and other end use processing is a consideration.
Several marking technologies use functional silicone release fluids in order to aid the wetting of the release surface by chemical means. This functionality is multi-faceted in nature, in that it can fortify the release layer through the chemical attachment of functional groups to the surface, it enables more uniform coverage of the release layer, and it can improve wetting of the release fluids that may not wet/spread as effectively or as quickly as they would without the benefit of functionality. The foremost example of functional release fluids is amine functional silicone, commonly used in conjunction with anodized aluminum, fluoropolymer and fluoroelastomer surfaces. As an example, nonfunctional silicone does not inherently spread or wet a fluoroelastomer surface well at the nominal viscosity and temperature ranges suited to the application. The silicone is easily removed from the surface and its wetting behavior does not allow it to wet as uniformly or tenaciously as is necessary for sustained release performance. When the release fluid fails, ink or toner can then contact the drum surface, resulting in numerous shortfalls in performance, such as transfer offset failures.
Amine functional silicone consists of a blend of nonfunctional and functional components. The amine functional component is renewable and replenishable, and can both create and bond with unsaturation in polymer backbones. This enables the spread and release performance of the non-functional component, which spreads and remains by virtue of chain entanglement and affinity between the functional and non-functional parts.
Analogous to the previously described situation is the use of functional perfluorinated polyether (PFPE) or other fully fluorinated fluids as release agents. The defects and maintenance requirements associated with these failure modes when used with silicone oil necessitate increased user intervention, increased cost of operation, and more complex system designs. The root cause of many failures in marking systems requiring release agents is the interaction and solubility between toner and ink constituents and the silicone release agent. This interaction and its effects on system performance have been extensively studied and mapped. The use of non-interactive PFPE fluids as release agents in these marking technologies can eliminate these interactions and provide a renewable, through effective filtration, release agent to improve subsystem life and reliability, thereby reducing maintenance and run costs.
There exists a need for a release agent to be used in color marking applications where higher speed, improved release life, and/or cost reduction is desirable. While these fluorinated fluids may be used in their currently commercially available configuration, without additional functionality, more demanding applications may warrant the use of functionalized versions of fluorinated fluids. Such functional molecules are known and can be prepared in a manner described in the following article: Tonelli Claudio, Gavezotti Piero and Strepparola Ezio. Linear perfluoropolyether difunctional oligomers: chemistry, properties and applications Journal of Fluorine Chemistry, Volume 95, Issues 1-2, 4 Jun. 1999, Pages 51-70.
In addition, a need still exists for a release agent, which provides sufficient wetting of the imaging member, but still has little or no interaction with copy substrates such as paper, so that the release agent does not interfere with adhesives and POST-IT® notes (by 3M) adhering to the copy substrate such as paper. It is further desired that the oil not prevent ink adhesion to the final copy substrate. In addition, it is desired that the release agent not react with components of the ink. Also, it is desired to provide a release agent that enables increase in life of the imaging member by improved spreading of the release agent.